AN3271

Various connections of push-buttons

Doc ID 17933 Rev 2

13/29

6.2

Alternative single button control

The hookup in Figure 10 might suggest identical functionality compared to hookup in

Figure 9. However SR input is monitored for falling edge after power-up and must not be

grounded permanently. In addition some flavors have internal pull-up resistor connected to

SR input, which would create additional current. Therefore hookup in Figure 9 is

recommended for single button control.

Figure 10.

Alternative single button control

1.

Internal pull-up resistor is available on STM660xA, STM660xB, STM660xC and STM660xD.